Document Detail

Direct versus indirect pressor and vasoconstrictor actions of angiotensin in conscious dogs.
MedLine Citation:
PMID:  2858448     Owner:  NLM     Status:  MEDLINE    
To determine the importance of the direct and the indirect pressor and vasoconstrictor actions of angiotensin II (ANG II), experiments were conducted in conscious dogs 2 to 8 weeks after instrumentation with aortic catheters and aortic electromagnetic flow probes to measure arterial pressure and cardiac output. Total peripheral resistance was calculated by an on-line digital computer. Pretreatment with propranolol eliminated complicating inotropic effects of norepinephrine, released by the indirect actions of ANG II. The pressor and vasoconstrictor responses after ganglionic blockade, in either the presence or absence of arterial baroreceptor nerves, were considered to be the direct effects of ANG II. In conscious dogs, systemically administered ANG II (32 ng/kg bolus) increased mean arterial pressure by 38 +/- 3 mm Hg, total peripheral resistance by 37 +/- 2 mm Hg/L/minute, and decreased heart rate by 15 +/- 2 beats/minute. After arterial baroreceptor denervation, administration of ANG II increased mean arterial pressure by 88 +/- 7 mm Hg, total peripheral resistance by 54 +/- 4 mm Hg/L/minute, and heart rate by 12 +/- 2 beats/minute. After arterial baroreceptor denervation and ganglionic blockade with hexamethonium, administration of ANG II increased mean arterial pressure by 53 +/- 8 mm Hg, total peripheral resistance by 27 +/- 3 mm Hg/L/minute, and left heart rate unchanged. These results indicate that in the conscious dog without baroreflex buffering nearly one-half of the pressor and vasoconstrictor actions of angiotensin are not direct, but are mediated by the autonomic nervous system.
A M Fujii; S F Vatner
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Hypertension     Volume:  7     ISSN:  0194-911X     ISO Abbreviation:  Hypertension     Publication Date:    1985 Mar-Apr
Date Detail:
Created Date:  1985-05-16     Completed Date:  1985-05-16     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  7906255     Medline TA:  Hypertension     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  253-61     Citation Subset:  IM; S    
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MeSH Terms
Angiotensin II / pharmacology*
Blood Pressure / drug effects*
Cardiac Output / drug effects
Ganglionic Blockers / physiology
Heart Rate / drug effects
Pressoreceptors / drug effects,  physiology
Propranolol / pharmacology
Vascular Resistance / drug effects
Vasoconstriction / drug effects*
Grant Support
Reg. No./Substance:
0/Ganglionic Blockers; 11128-99-7/Angiotensin II; 525-66-6/Propranolol

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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